Oil pollution control and fire extinguishing apparatus and method

ABSTRACT

A device for extinguishing gas and oil well fires, particularly multiple-well, offshore installations, and for preventing loss of oil to the surrounding area after fire extinction comprises a hood adapted to be placed over the well site, the hood having a curved interior upper wall which deflects the gushing oil into a catch basin from which it can be pumped away.

United States Patent Sam M. Verdin 2600 Breton Drive, Marrero, La. 70072 [21] Appl. No. 18,846

[22] Filed Mar. 12, 1970 [45] Patented I Jan. 12, 1971 [72] lnventor [54]- OIL POLLUTION CONTROL AND FIRE EXTINGUISHING APPARATUS AND METHOD 4 Claims, 5 Drawing Figs.

[52] US. Cl 169/2, 166/75 [51] Int. Cl A62c 3/00 [50] Field of Search 169/2;

Primary Examiner-Lloyd L. King Attorney-Cushman, Darby & Cushman ABSTRACT: A device for extinguishing gas and oil well fires, particularly multiple-well, offshore installations, and for preventing loss of oil to the surrounding area after fire extinction comprises a hood adapted to be placed over the well site, the hood having a curved interior upper wall which deflects the gushing oil into a catch basin from which it can be pumped away.

PAIENTEnJAmIsn Y 3554.290

sumznrz Q v INVIZNTOR 2 :4 jfifZ'KJ/N ATT( JRNEYS OIL POLLUTION CONTROL AND FIRE EXTINGUISHING APPARATUS AND METHOD DISCLOSURE This invention relates to ,a methodand apparatus for combatting gas and oil well fires and for'collecting and removing oil from the site so as to prevent pollution of the area while oil is still flowing from the well. p v Three of the major problems associated with an oil well fire are the difficulties encountered in extinguishing the fire initially, preventing 'reignition, and preventing. pollution of the surrounding area with oil during the period between fire extinction and capping of the well. More specifically, the oil loss problem arises because after the fire has been put out, the oil continues to gush from the broken well head usually under plugging the well head insome manner, as by lowering a special blowout preventer over the well head. This is often a difficult and time-consuming job due to the danger of reignition and the presence of the spurting oil;

The ,pollution problem is particularlysevere in :thecase of offshore, multiple-well installations where a plurality of well has previously been extinguished. According to the principles of the present inventionthere is provided a special hooklike structure of sufficient size that it canbe loweredover the well site so as to overlie the well headsand either fullyor partially enclose the entire site, including the platform on which the well heads are located. The hood will of course be of largesize and weight and must be transported and manipulated. by heavy duty floating cranes of the kind available in the offshore oil well industry. The interior of the special hood presents a downwardly facing generally. concave deflecting surface-to the spurting oil to direct it into a-catch basin or the like within the hood, thereby substantially preventing the oil from dropping into the sea. The collectedbil'ispumped through oneor more pipes to a storage structuresuch as a barge or other vessel or a land-based tank installation if thewellsite is close to shore. The upper wall of the hood is provided with one or more hatches or the like through which well-cappingoperations' may becarried out from a floatingvessel carryingthenecessarycquipment. The techniques employed in capping a" broken well head are usually the responsibility of an experienced specialist and form no part of the present invention.

. The hood may be provided with -piping and valving for directing fire extinguishing fluids-such as water or drilling mud on to the well site afterthe hood is in place. There may also be provided piping and valving for directing streamsof water at l the spurting oil or along the curved deflecting surface to assist in directing the oil toward the catch basin.

If the hood is lowered'over the well site to an elevation at high underground pressure. The flow of oil is stopped only by which'its edges become submerged, it willgenerally be necessary to provide one or more outlet pipesfor venting the gas which often accompanies theoil escaping'from the well.

The invention will be further understood from the following more detailed description ofanexemplary embodiment illustrated in the drawing in which:

FIG. 1 is a schematic perspective view do well site enclosure embodying the principles of the present invention;

FIG. 2 is a schematic vertical sectional .view ofthe enclosure of H6. 1; and p v FIGS. 3, 4 and-5 are schematic views'illustrating the placing of the enclosure overan offshore well site.

As previously described, the present invention provides an place over an offshore well site by means of equipment available in the offshore oil well industry. Such an enclosure is illustrated schematically at 10 in the drawings. it being understood that the exterior shape of the enclosure is of no great importance. In the illustrated embodiment the enclosure i0 is defined by two spaced-apart vertical side walls 12, a vertical end wall 14 and an inclined top wall 16. The size of the enclosure 10 is such that it will cover the largest well site that it is designed for. For example, a typical offshore platform might be60 feet square and 60 feet above water level and support l2 well heads. The walls 12, 14 and 16 may be of sufficient thickness to render the enclosure self-supporting, or they may be of thinner construction reinforced with internal or external bracing.

An important feature of the enclosure 10 is that it include an interior oil-deflecting surface capable of deflecting upwardly gushing oil in'a lateral directionv toward a collecting basin 18. In the illustrated embodiment the inner surface of the top wall 16 provides the deflecting surface. The top wall lower end to itsupper end, the illustrated shape is not critical.

If desired, the deflecting surface may be defined by a separate structure suitably supported from the walls which define the enclosure 10.

The oil catch basin l8 extends from one side wall 12 to the other and is disposed adjacent the rear wall 14 in a position to catch the oil which has been deflected upwardly and rearwardly by the wall 16, as shown by the arrows 20 in FIG. 2. Also schematically shown in FIG. 2 is an offshore platform 22 supported above the level of the sea 24 by legs26 and having a plurality of well heads 27 projecting therefrom. As previously described, when a well'head has been ruptured or brokenoil flows from the head under such pressure that it spurts or gushes to a considerable height. When the enclosure 10 has been placed over the site, the oil will strike the lower deflecting surface of the wall 16. i

' In order to aid in deflecting the oil along the deflecting surface streams of water may be injected along the surface by means of suitable jets 28. Valved water supplypipes 3.0 are connectable to a pressurized source of water, such as pumps 32 carried by a service vessel 34 and adapted to draw water from the sea.

It isusually necessary to provide one or more vent pipes, such as shown at 36, for releasing gas from the enclosurejtfl, since many offshore wells are dualgas-oil wells. Ventpipesare particularly necessary when the enclosure 10 is lowered. into contact with the'sea thereby preventing escape of g asyaround the lower edgesof the enclosure 10. In use the vent-pipe 3.6gis connected to along pipe 37 to convey the gasrtoa'remote' glocation where it can be burned. The enclosure 1;0:may-,al o.-;include pipes 38. for injecting fire extinguishing liquids; SLlQhgaS water or drilling mud on to the platform 22. These -p ipes3,8 which may be mounted on'the sidewalls l2 -canb,e-.s upp1ied A with the pressurized liquid from pumps on the seruiee, vessel When all the necessary equipment for capping.:the-.w.ell heads 12 has'been assembled, the capping operationswillabe carried out through the walls of the enclosure 10;.fonexample throughhatches 40 which are fitted with slidingcoversAZnAs previously explained the capping operation involves the loweringofa blowout preventer assembly over thevdamaged open end of awell head and operating the assembly tocu't off the flowof oil. The assembly and other equipment are brought to the site by the service vessel 34 or other vessel-equipped with one or more cranes, and after one of the covers 1 is:slid

- back, the capping operations are effected'through the-respective hatch 40. The hatches 40 should be relatively small so as to permit as little oil as possible to escape during the capping operation. The power mechanism for sliding the covers 42 may be carried by the enclosure 10 or by the service vessel.

FIGS. 3, 4 and 5 illustrate a typical sequence of steps by which the enclosure may be placed over the platform 22 which for purposes of illustration may be assumed to have one or more spurting well heads but no fire. In FIG. 3 the enclosure is shown suspended by cables 44 and booms 46 carried by a vessel 48. The forward end of the enclosure has been raised above the rear end so as to clear the platform 22. Then the forward end of the enclosure 10 is lowered, as seen in FIG. 4, and the entire enclosure is lowered over the platform 22. In the illustrated embodiment the platform 22 is lowered into contact with the sea 24 although this is not always necessary or even possible. Oil which collects in the basin 18 is carried off through an outlet 50 in the rear wall 14 and through a flexible line 52 by gravity or by means of a pump 54 carried on a barge 56.

If there is an oil fire on the platform 22 the operations shown in FIGS. 3, 4 and 5 will be carried out in a similar manner, except that no attempt to carry off the oil will be made until after the fire has been extinguished by smothering and with the aid of liquids pumped through the pipes 38. These same liquids will also serve to cool the platform 22 to prevent reignition by hot spots.

It will be understood that the location of the hatches 40 may vary from that illustrated and that the enclosure will be moved in horizontal directions by the cables 44 and booms 46 in order to align a given hatch 40 with a desired well head 27.

I claim:

1. Apparatus for use in enveloping an offshore multiplehead oil well site for collecting oil flowing under pressure from one or more damaged well heads and for extinguishing a tire,

said apparatus comprising: a hoodlike structure of suflicient size to cover the well site, said structure having an open bottom permitting the structure to be lowered over the well site and having an upper wall and a side wall for at least partially surrounding the sides of the well site; oil deflecting means within said hoodlike structure including an inclined surface which overlies the well heads at an angle such that oil spurting upwardly from a well head against said surface is deflected laterally; catch basin means within said hoodlike structure disposed to receive the deflected oil; pipe means for carrying away oil from said catch basin means; and hatch means associated with the upper wall of said hoodlike structure through which well-capping operations can be effected from a location outside said structure.

2. Apparatus as in claim 1 including liquid injection means carried by said structure for injecting fire-extinguishing liquids into the interior of said structure.

3. Apparatus as in claim 1 including means carried by said structure for directing a current of water along said inclined surface to assist in deflecting the flow of oil toward said basin means.

4. A method of extinguishing and capping a burning offshore oil well comprising: transporting to the well site an open-bottomed enclosure of sufficient size to envelop the well site; lowering the enclosure over the well site; injecting fireextinguishing liquid through the enclosure on to the well site to extinguish the flames; deflecting gushing oil from the well site to a retaining structure within said enclosure; pumping oil from the retaining structure to a remote tank; and lowering well-capping equipment from a location outside the enclosure through the enclosure into engagement with a well head and effecting capping of the well head. 

2. Apparatus as in claim 1 including liquid injection means carried by said structure for injecting fire-extinguishing liquids into the interior of said structure.
 3. Apparatus as in claim 1 including means carried by said structure for directing a current of water along said inclined surface to assist in deflecting the flow of oil toward said basin means.
 4. A method of extinguishing and capping a burning offshore oil well comprising: transporting to the well site an open-bottomed enclosure of sufficient size to envelop the well site; lowering the enclosure over the well site; injecting fire-extinguishing liquid through the enclosure on to the well site to extinguish the flames; deflecting gushing oil from the well site to a retaining structure within said enclosure; pumping oil from the retaining structure to a remote tank; and lowering well-capping equipment from a location outside the enclosure through the enclosure into engagement with a well head and effecting capping of the well head. 